From f91d18eaa946b2d2ea5a9334fb099c3e409ad2d1 Mon Sep 17 00:00:00 2001
From: Sourabh Singh Tomar <SourabhSingh.Tomar@amd.com>
Date: Thu, 20 Aug 2020 16:11:22 +0530
Subject: [DebugInfo][flang]Added support for representing Fortran assumed
 length strings

This patch adds support for representing Fortran `character(n)`.

Primarily patch is based out of D54114 with appropriate modifications.

Test case IR is generated using our downstream classic-flang. We're in process
of upstreaming flang PR's but classic-flang has dependencies on llvm, so
this has to get in first.

Patch includes functional test case for both IR and corresponding
dwarf, furthermore it has been manually tested as well using GDB.

Source snippet:
```
 program assumedLength
   call sub('Hello')
   call sub('Goodbye')
   contains
   subroutine sub(string)
           implicit none
           character(len=*), intent(in) :: string
           print *, string
   end subroutine sub
 end program assumedLength
```

GDB:
```
(gdb) ptype string
type = character (5)
(gdb) p string
$1 = 'Hello'
```

Reviewed By: aprantl, schweitz

Differential Revision: https://reviews.llvm.org/D86305
---
 llvm/lib/Bitcode/Reader/MetadataLoader.cpp | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

(limited to 'llvm/lib/Bitcode/Reader/MetadataLoader.cpp')

diff --git a/llvm/lib/Bitcode/Reader/MetadataLoader.cpp b/llvm/lib/Bitcode/Reader/MetadataLoader.cpp
index 6fccb312164b..821185e46c04 100644
--- a/llvm/lib/Bitcode/Reader/MetadataLoader.cpp
+++ b/llvm/lib/Bitcode/Reader/MetadataLoader.cpp
@@ -853,6 +853,7 @@ MetadataLoader::MetadataLoaderImpl::lazyLoadModuleMetadataBlock() {
       case bitc::METADATA_SUBRANGE:
       case bitc::METADATA_ENUMERATOR:
       case bitc::METADATA_BASIC_TYPE:
+      case bitc::METADATA_STRING_TYPE:
       case bitc::METADATA_DERIVED_TYPE:
       case bitc::METADATA_COMPOSITE_TYPE:
       case bitc::METADATA_SUBROUTINE_TYPE:
@@ -1325,6 +1326,20 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
     NextMetadataNo++;
     break;
   }
+  case bitc::METADATA_STRING_TYPE: {
+    if (Record.size() != 8)
+      return error("Invalid record");
+
+    IsDistinct = Record[0];
+    MetadataList.assignValue(
+        GET_OR_DISTINCT(DIStringType,
+                        (Context, Record[1], getMDString(Record[2]),
+                         getMDOrNull(Record[3]), getMDOrNull(Record[4]),
+                         Record[5], Record[6], Record[7])),
+        NextMetadataNo);
+    NextMetadataNo++;
+    break;
+  }
   case bitc::METADATA_DERIVED_TYPE: {
     if (Record.size() < 12 || Record.size() > 13)
       return error("Invalid record");
-- 
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